Just bought a Bushmaster M4A3 and I am looking to put an optic on it. I am a relatively new shooter and only shoot for sport at this point. (Though I put in a lot of range time with my pistols to work on getting to a competitive level.) I enjoy quick target location but also do alot of desert shooting so it would be nice to have some accuracy at a distance too. I don't want to break the bank and do not know where to begin or what any of the specs mean?? Thanks for any help or suggestions.